Pests or nute burn?

[Badfinger]

Hi, I'm growing in Happy Frog soil. At 5 weeks I thought it might be time to start nutes. So I did a 1/2 strength feed of Big Bloom and Grow Big. Then about 3 days later I started getting deformed new growth and wrinkled and shredded looking leaves on the new growth. My first thought was Nitrogen Toxicity, so I did a flush in hopes of washing out any excess nutes. But the holes and shredded appearance resemble the look of being munched on. I have seen no pests, but I imagine that does not mean they arent there.
A side note that also confuses me, I always ph my water to 6.5, yet interestingly, I ph'd the runoff after the flush and got a ph of 4, which now really baffles me. Any opinions?

 

[Sheriffatman]

Looks like that’s been munched on. Have you checked the underside of the leaves? Maybe if you have a jewellers loupe or macro of any kind , that may help you spot anything suspect.

 

[Badfinger]

Looks like that’s been munched on. Have you checked the underside of the leaves? Maybe if you have a jewellers loupe or macro of any kind , that may help you spot anything suspect.

I been looking under the leaves constantly and never see anything. I havent picked up my magnifier yet, being a 1st time grower I'm still researching which one I'm gonna go with. But as a precaution, I'm going to pickup some Capt jack spray and powder today, just to be on the safe side.

 

[Sheriffatman]

New to all this myself bud, just one grow under my belt so far. But your at the right place, good bunch around here and always happy to help. Stick around.

 

[Badfinger]

New to all this myself bud, just one grow under my belt so far. But your at the right place, good bunch around here and always happy to help. Stick around.

It turned out to be a Leaf Roller caterpillar. My god that little sob was destructive. He was wrapped up inside the tip of the main cola. He was fast too, every time I was about to grab him, he would repel down on a silk rope to the next lower level. They look just like a Fungus Gnat Larvae, long and yellow with a black head, but this guy was about 1/4" long. Way bigger then a Gnat Larvae.